Currently keys are used for a wide variety of applications that comprise a mechanical or electromechanical cipher, which carries coded information. One example of the latter is keys described in European Patent 472495 which has a specific mechanism located on opposed edges of the key which co-operates with a corresponding mechanism built into a mating lock cylinder before a locking system incorporating the lock cylinder may be opened.
While such keys are simple to use, it will be appreciated that the level of security is not high because there are no means currently available for verifying that the person using the key is an authorised user. This means that while a conventional mechanical or electromechanical lock operated by a key presents physical access to a building such a key may be readily copied or it may be lost or given to other persons who may then gain access to the building on an unauthorised basis. Thus, physical access to the building is provided by those in control of the key.
Conventional biometric control systems are well known and refer to encoding of a person's specific biometric features into a memory of the biometric control apparatus with an external process (e.g. storage memory, matching algorithm and return signal). A coded version of an authorised biometric feature can be stored. When verification is required, it is necessary for the user to present his biometric characteristic feature to the biometric control apparatus, which then compares the biometric characteristic feature with the authorised biometric feature. If a match occurs, then the biometric control system permits access to a facility controlled by the biometric control system.
Biometrically secured control systems for preventing unauthorised use of vehicles are described in U.S. Pat. No. 5,867,802. This reference describes a method and system for restricting use of a vehicle to person(s) whose fingerprints match biometric data stored within a memory in the control system of the vehicle. A user's digitised fingerprints are stored in a ROM in the BIOS of a microcontroller or in a ROM accessed by a microcontroller. The microprocessor's primary task is that of executing instructions, which are related to the operation of the vehicle such as regulation of the fuel flow rate, and other tasks. Before the microprocessor can execute its instructions related to the primary task, it must complete and exit a conditional loop of instructions that relate to validating the user's “real input” biometric data. Real scanned fingerprints must be compared with fingerprints(s) stored in ROM. If the result of the comparison is a match, then the operating loop is satisfied and the microprocessor can execute its instructions relating to operation of the vehicle. In U.S. Pat. No. 5,607,802 use is made of a conventional fingerprint scanning device and related circuitry coupled to the microprocessor. A key operated ignition switch is coupled to the microprocessor to provide a signal for providing power to the microprocessor before it may control operations related to the vehicle.
Another example of biometrically secured control systems is described in U.S. Pat. No. 5,915,936 which refers to a firearm which incorporates a pressure sensor for sensing grasping of a butt section of the firearm by a palm of the user as well as a scanning sensor for scanning a palm print of the user and generating a data signal representative of the scanned palm print after actuation of the pressure sensor. The firearm can only be used by authorised users wherein a memory unit stores data signals representative of the authorised users.
U.S. Pat. No. 5,987,155 refers to a biometric information input device having an integral smart card reader. The device provides co-operative operation of the smart card and the input device to provide user specific processing of biometric information provided by the user. Examples of biometric input devices referred to in this reference are those incorporating a microphone or those which comprise a contact imaging device such as a fingerprint scanner.
The abovementioned prior art references are illustrative of biometric control systems which can only be operated upon use of a vehicle ignition key as described in U.S. Pat. No. 5,867,802, a pressure sensor in the case of U.S. Pat. No. 5,915,936 or a smart card in the case of U.S. Pat. No. 5,987,155. It therefore will be appreciated that such conventional biometric control systems are non-versatile in being restricted to a specific application, and also require the use of additional structure relative to the specific application. Thus for example the biometric input device of U.S. Pat. No. 5,987,155 requires as an essential component a card slot for acceptance of the smart card.
It is an object of the present invention to provide a biometric key, which may reduce the disadvantages of the prior art, discussed above.